Fluid capacity issue

[Ellen B]

Hi everyone, I've got a Kubota L2501 with a hydraulic fluid capacity of 6.2 gallons. I just performed the 50 hour service, and changed out my hydraulic fluid as part of that. When refilling it I poured in roughly 5.5 gallons, and then ran the tractor for few minutes before topping it up, because I'm unsure if I need to circulate the fluid to get a correct reading on the sight glass. When I checked the sight glass, the fluid line was in there so I didn't add any more fluid.

Yesterday I removed the backhoe, attached the three point hitch, and did about an hour of work with a box blade. The tractor was operating just fine, but when I got off to take a break I noticed that the fluid was gone from the sight glass. I had purchased 7.5 gallons of fluid for the change out, and I added the remainder of that but there's still nothing in the sight glass. This morning I purchased another jug of fluid, and have already added about a gallon to the tractor, still without getting it to come up to the sight glass.

At this point, I've added about 8.5 gallons of fluid when the manual says I should've needed 6.2. I didn't spill any during the refill or backhoe disconnect, and I'm 100% positive that none leaked out while it was parked. I hadn't operated the three point hitch before yesterday (after the fluid change) in case it matters. Could there be that much fluid stuck in the backhoe (BH77, can't find fluid capacity specs though)? Or is there something else I'm missing? I'm hesitant to continue adding fluid until I figure out what is going on.

Thanks for your advice!

 

[Scook222]

If you have a front end loader on your tractor, lower it to the ground and lower the 3 point hitch. If you front end loader is raised several feet off the ground the fluid will not be in the sight glass. I have the same tractor as you and check mine with the bucket level on concrete and the 3 point hitch raised to be able to see the air bubble at the top of the sight glass. The bh77 shouldn’t affect the fluid level on the tractor unless it was just installed from the factory. With that much fluid in the tractor, you should be able to see it where you add the fluid. If there is no leaks, it is definitely over full.

 

[RickB]

Oil level is probably well above the sight glass. I hate them, they are a stupid idea.

 

[Ellen B]

The bucket and three point hitch were both lowered when I was filling or checking it. Are you saying I should be raising it?

When I did the service and filled the fluid up to the sight glass, the tractor was level. It hasn't been level since then as I've been adding more, but it's not that far off. I can try leveling it again tonight, I need to put the backhoe back on though as there's literally nowhere level on my property and I need the outriggers to get it set right.

The back of the sight glass is white, and the fluid is a light amber color (Kubota SUDT2). I haven't had any issues reading it before, and I'm seeing plain white with no hint of color whatsoever. Is there a way it could be over full if I'm not seeing any fluid at all?

 

[Scook222]

The tractor needs to be level when you check it. I check mine with the three point hitch up and the bucket flat but rolled forward on the ground so I can see the bubble at the top of the sight glass. I was suggesting raise the front end loader and 3 point hitch up high so it will take some of the fluid out of the reservoir to see the sight glass with the tractor level to see how much it’s over filled. If the tractor was full before you added the extra, it should be over full even if you can’t see it in the sight glass on a slope. Can you face the sight glass to the downhill side to see if it fills up the sight glass.

 

[ericm979]

The loader and backhoe cylinders's volume of oil does not change much when you extend vs retract them. There's oil on both sides of the piston. The only difference between extended and retracted is the volume that the rod takes up. The backhoe cylinders and lines are already full of oil. Putting the backhoe on does not take up a bunch of oil.

It's likely that the problem is that you're checking when the tractor is not level. Since the sight glass is at the back of the long transmission case, it would not have to be far off level to greatly change the reading at the sight glass.

Also some tractor fluid is clear. It can be very difficult to see the fluid in the glass when the line is above the glass. It looks like it's empty. They make oil dye to address this problem.

 

[Ellen B]

Alright, so I brought the tractor back to the house, reattached the backhoe, and used the outriggers to level it. Still nothing in the sight glass. Immediately after changing the fluid when doing the 50 hour service, I was able to clearly see the white background of the sight glass through the bubble in the hydraulic fluid, and that was with brand new oil, so I'm certain that I'm not mistaking a full sight glass for an empty one.

After that I tried positioning it in a bunch of different ways on a slope, and still got nothing in the sight glass.

Barring someone suggesting something else to try first, I guess I'm going to drain the fluid tomorrow morning and slowly put it back in. If I do that, should I be able to read the sight glass in real time as I'm filling it, or do I need to run the tractor to circulate the fluid?

And thanks for all your responses!

 

[oldnslo]

Ellen
Can you drain it slowly a little at a time while watching the site gauge? If yes this would save the trouble of drain and refill.

Other option can you stick a small rod or stiff wire in through the fill port to get some idea on the oil level in reference to the sight gauge. May not give exact level but could provide a reference on where the oil level is.

Not sure your tractor will accommodate the manual level check though.

 

[Ellen B]

I can definitely drain it slowly, hadn't thought of that since there's no fluid in the sight glass for me to watch, but it can't hurt and like you said may save me some hassle and mess.

And great tip on checking the level with a piece of wire. Based on the fill cap location and orientation I believe it'll be possible, unless there's something in the way of the wire on the inside of the tank. I'll try that later this morning after I get the goats moved into a new paddock, those goofballs have their priorities mixed up and don't seem to care about the tractor at all :confused3:

 

[Ellen B]

Ok, checked it with a wire and the fluid level is definitely above the sight glass. Could someone please let me know if I should be able to read the sight glass in real time as I'm draining or filling fluid, or if I need to run the tractor for a bit to circulate the fluid in order to get an accurate reading?